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The tale of everyone's genetic history

Adam Rutherford engagingly tells the tale of everyone’s genetic history.

Back when I was in high school, scientists thought ­Ramapithecus, which lived 14 million years ago, was on our direct family lineage. When I taught ­secondary school biology, the discovery of the fossil “Lucy” had moved things on a bit: here was a definite hominin from 3.2 million years ago. Since then, not only have scientists continued to find new fossils, but genetics has galloped ahead as well. We can now compare the genomes of our own species and the Neanderthals, and look back in time at our own evolution and our ancestors’ migrations around the globe.

That genetic unravelling of our past is a complex tale and Adam Rutherford’s A Brief History of Everyone Who Ever Lived presents it in an engaging and ­compelling way that’s accessible to anyone with an interest in science and their own history. The “everyone” of the title refers to modern humans – roughly 107 billion of them – but as Rutherford says, our pedigrees “fold in on themselves, the branches loop back and become nets, and all of us who have ever lived have done so enmeshed in a web of ancestry”.

Recorded history goes back only a few thousand years. Genetics lets us fill in some of the gaps as well as peer further back in time. In telling our history, Rutherford also provides an excellent introduction to DNA, inheritance and the tools we use to understand the ­molecular side of ­inheritance. I particularly liked the clever way he uses the structure of his sentences to show how mutations affect the genetic information, and how DNA sequencing works.

In the first part of the book, Rutherford reminds us that “we are no more or less evolved than any other creature … and the language we once used, where species were ‘higher’ or ‘lower’, no longer carries any [scientific] meaning”.

He looks at the early ­history of our species, ­including other closely related species such as the Neanderthals and ­Denisovans, whose genetic legacy is still found in many of us. Moving closer to our own time, he discusses Charlemagne, to whom all Europeans are related since our family trees become more and more entangled as we go back into the past; the role DNA played in ­identifying the remains of Richard III; and the last of the Habsburg princes, whose downfall was inbreeding – the family stopped ­outbreeding eight generations before the birth of Charles II, the last Habsburg to rule Spain. As Rutherford notes, “on a long enough timeline, we’re all inbred”, but the Habsburg timeline was much shorter than that, and its inbreeding much greater. Of the 34 royal infants born in the 30 years before Charles’ birth, one in two died – among common folk, infant mortality was around one in five.

The book’s second part tackles issues including race and eugenics. Race is a concept that’s been seriously abused in the past (Stephen Jay Gould’s 1981 book The ­Mismeasure of Man gives a good historical overview). Although there are certainly differences between ethnic groups, many studies have found that 85% of genetic variation occurs within the same “races”. The morphological differences are real, but underlaid by only 8% of total genetic ­variation: “Genetically, two black people are more likely to be more different from each other than a black person and a white person.”

These differences are fascinating, and in cases such as the sickle-cell mutation that confers protection against malaria, highly significant. They can also be used to track migration patterns (through types of earwax, for example) and cultural changes: the invention of dairying and its spread can be tracked via the genetic variant that allows us to digest lactose.

Outside race, those who are ­“different” are also often targeted. ­Eugenics was first ­proposed by the polymath Francis Galton, a cousin of Charles Darwin, but the concept has been the cause of much human misery, e­xtending well beyond the Nazi ­horrors of World War II. In 1970s America, black women with large families were being pushed into ­sterilisation with threats of losing welfare payments if they didn’t comply. Men were also sterilised, often on the basis of having a criminal history, but the hands of the state do seem to have fallen more heavily on women – up to 31 US states practised some form of eugenics during the 20th century.

This is a book about biology, evolution, ­history and culture all rolled into one. It deserves a wide readership and will probably generate some interesting conversations. I’ll be recommending it to all the teachers and students I know.

A BRIEF HISTORY OF EVERYONE WHO EVER LIVED: THE STORIES IN OUR GENES, by Adam Rutherford (Weidenfeld & Nicolson, $40)

Alison Campbell is a senior lecturer in biological sciences at the University of Waikato.

This article was first published in the February 4, 2017 issue of the New Zealand Listener. Follow the Listener on Twitter, Facebook and sign up to the weekly newsletter.